This invention relates to improvements in lifting magnets and, more particularly, to an improved terminal box for lifting magnets which is adapted to be secured onto the casing of magnets of various sizes and shapes.
Prior terminal boxes for lifting magnets have various shapes and configurations to facilitate the connection between the coil leads and the service leads and also to provide a moisture proof environment for such connections. In order to provide access into the box for making the connections, different types of cover plates are used. These cover plates are usually held on by bolts having heads extending above the cover plates. The plates, which are on the top portion of the terminal box housing, often extend over a portion or all of the top surface of the terminal box.
Typically, lifting magnets are subjected to severe abuse when used as a ram or a drop ball resulting in blows on the front, sides and top of the terminal box. Even under normal use, a magnet terminal box often receives hard direct blows. If a terminal box is of a style with wings, the wings are easily bent up by such blows. To prevent this bending of the winged portions of terminal boxes often requires the addition of long anchor bolts or the like within each wing in order to strengthen the wings against blows. Countersunk holes are often used in an attempt to protect the cover plate bolt heads from blows, but the material around the holes is simply peened in, which prevents the removal of the cover plate. Cover plate bolts are often sheared off, which results in the cover plates being partially or completely knocked off, permitting moisture to enter the terminal box cavity causing the magnet coil to ground to the case.
In addition, the corners of magnet terminal boxes are often badly dented and the sides slightly displaced by the different blows that the terminal box receives in operation. As a result, the internal electrical connections suffer mechanical damage or the water-tightness is lost.